Sunflower Star Landslide

Research diver Donna Gibbs was able to record on videotape a remarkable event that occurred at the time of an extreme low tide along the shoreline of West Vancouver, just east of Whytecliff Park. As Donna prepared to start a dive with Jeff Marliave at Kettle Point, the crew exchanged comments about the strong shoreline current, as well as the apparent red tide condition. The sea surface was also at a record 23 degrees Celsius. Donna and Jeff went down on a planned drift dive toward the west, counting rockfish at an artificial reef and along natural shoreline reef areas that have been monitored for this entire decade.

The water clarity was excellent at depths below the red tide, and the dive plan proceeded normally until an area was reached where vast numbers of the giant sunflower sea star were covering the rock surfaces. At this point, a down-welling component of the shoreline current was evident and the sea stars were rapidly moving down the slope of the rock. The sea stars were traveling so quickly that they were running over each other, creating slow-motion landslides of sea stars tumbling down the slope.

We can only surmise that the the red tide or warm water may have come into contact with the sea stars and stimulated flight. The sunflower star is both the largest and the fastest sea star in the world. Sunflower stars have up to 26 arms bearing on the order of 15,000 little tubefeet that somehow coordinate movement that in most species is too slow for people to detect. These sea stars were truly sprinting, moving at about ten centimeters per second.

For more information about fish research at the Vancouver Aquarium please contact Kevin Kaufman: kevin.kaufman@vanaqua.org